Bought a red one tonight at an auction for peanuts! Think it's seized as the kickstart won't budge at all! Looks like an early 80's one but the spark plug sits at the front of the engine facing the front wheel and it has a fill hole for oil??? Thought 50's just used the normal petrol/ 2 stroke oil mix?? I'l get pics up asap

 

Prob the gearbox fill hole if the oil hole is on the casing ,yer get pics up not seen one in years !

 

I have had a a few early 80's mx bikes.My mate does complete restorations on most 80's mx bikes for a living.I have never seen a YZ with the plug on the front of the head.Are you sure its not a pw50 ?.They are like that on the pw 50 and 80.

 

http://www.ebay.co.uk/itm/Yamaha-YZ-...item4156480383

 

Thats what it must be then! The ones ive just searched are similair to the one i have! Its a really old one! How can i tell if its a 50 or 80??

 

look on ebay and see if the pics look like what youve got

 

The pw's I've seen have a shocker visible at the back where as the one I have is completely different and the same as the yz! Maybe it has the pw engine?? I'l get pics up tomorrow so you's get a better idea!! The one on eBay has a different shaped seat

 

I had a pw and thats not like the one in the photos

 

PW 50,s are loads smaller than an 80.The 50 is auto and the 80 is three speed semi.My lad had a 2004 pw80 for about 3years.Absolutely mint bike,2 years old when he got it.Never had to do a tap to it except normal g/box oil changes.Far superior than the Chinese 4 stroke crap.You say its red ? all red or red seat,what colour are the plastics,white ?.When you can,stick some pics on.Some one will tell you what it is.

 

this one has gears! think its white underneath that brutal paintjob its had lol! i want to rebuild the engine but ive never worked on a motorbike engine before? im handy with spanners and can work with car engines but dont have a clue about bikes? im guessing this one is an 80cc then if it has the gears? no clutch lever in sight which puzzled me :s

 

found this on the net! 1982 pw80 identical to mine!

 

PW 80 you have there.If its white underneath its an older version.Makes no difference.These are great,bullet proof really.Take the exhaust off at the front to see if the restrictor is in there.Its only a washer and will just pull out with your fingers.You should know by riding it really.If it revs ok no restrictor,if it seems to struggle it may be still in.The perfect bike for any young un to learn on imo.My lad used to be on and off the seat flat out on his and I would be along side on my 250 or 450.He progressed to a RM65 after his pw.Dead easy for parts and to work on,there is nothing too them.Let me have a think and I will see if I can remember how i.d. the year .Compare your frame number with this one *4bc-094593*.
Ah too slow,I was trying to find that frame number.Cant remember what year they went blue.At least you sorted now

 

This was my lads,a few stress marks on the plastics where he went down a couple of times


then got this,it lifts with me on it

 

Rm looks nice! Im going to rebuild this and get it looking good so my daughter can go it! Cheers for your help mate and cheers to everyone else for the input, much appreciated!!

 

Get the head off then the left hand casing so you can get to the fly wheel ,lots of WD40 down the bore then rock the fly back and forth ,you may just have rings rusted to the bore .

 

Looks like an old dt its defo not a yz.

 

It's a pw80

 

If it wont turn over you may aswell take the head and barrel of(10 mins).What is it exhaust off and for nuts for the head.Be carefull these dont snap,if they do once you have the barrel removed you should be able to change the threaded bar pretty easy.Its just a matter of course removing it anyway for a new piston and maybe a rebore.Its all cheap as chips anyway.Give the crank a yank up and down whilst your there because if it has seized from lack of two stroke (is the autolube connected up,oil bottle under seat) the crank gets its lube from the fuel mixture so the bearings in that may be goosed.I will keep an eye on this thread

 

Cheers for the info mate, il have a look at it tomorrow! I took the seat and plastics off today and i could see that autolube tank which i wondered what it was for lol thanks again for the info

 

nice project, every youngens dream learner bike, got my 82 cr80 all stripped down ready for the restore

 

sell it to me, i love kids dirt bikes

 

Its a PW80 Id say

Kids bikes look so cool